//=============================================================================
//     _   _                               ____                _  _          
//    | | | |  __ _  _ __   _ __   _   _  / ___|  _ __   _ __ (_)| |_   ___ 
//    | |_| | / _` || '_ \ | '_ \ | | | | \___ \ | '_ \ | '__|| || __| / _ \
//    |  _  || (_| || |_) || |_) || |_| |  ___) || |_) || |   | || |_ |  __/
//    |_| |_| \__,_|| .__/ | .__/  \__, | |____/ | .__/ |_|   |_| \__| \___|
//                  |_|    |_|     |___/         |_|                         
//
//                     HappySprite - We make sprites happy
//
// Copyright (c) 2007 by Tank Monkey Games
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//=============================================================================

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.Xna.Framework;

namespace HappySprite.SceneGraph
{
    public class PerspectiveCamera : Camera
    {
        float aspectRatio = 4f / 3f;
        float fieldOfView = MathHelper.PiOver4;

        public PerspectiveCamera()
        {
            SetViewportBounds(0f, 0f, 640f, 480f);
        }

        public float AspectRatio
        {
            get { return aspectRatio; }
            set { aspectRatio = value; }
        }

        public float FieldOfView
        {
            get { return fieldOfView; }
            set { fieldOfView = value; }
        }

        public override void SetViewportBounds(float left, float bottom, float right, float top)
        {
            float halfWidth = (right - left) / 2f;
            float halfHeight = (top - bottom) / 2f;

            float z = halfHeight / Trigonometry.Tan(FieldOfView / 2f);

            World.Rotation.SetIdentity();
            World.Position = new Vector3(left + halfWidth, bottom + halfHeight, z);

            AspectRatio = halfWidth / halfHeight;
        }

        protected override Matrix GetProjectionMatrix()
        {
            return Matrix.CreatePerspectiveFieldOfView(FieldOfView, aspectRatio, NearPlaneDistance, FarPlaneDistance);
        }
    }
}
